Hi, I would like to get opinions and ideas on a finding and proposed solution for memory intensive nodejs actions that I found during debugging of a related issue.
*Problem Statement* The problem is that the node js problem does not seem to have enough idle time in a serverless world to run garbage collector. That can be seen by running a 512MB action that allocates and free 128MB memory. As a result you can see that every 5th invocation run into an application developer error because OW's DOS protection kills the container at the 512MB limit. (disclaimer: the action is a very synthetic action doing nothing else which might reduce the time for the GC to jump in, like downloading a video/image, ...) You can see the details in the following PR: https://github.com/openwhisk/openwhisk/pull/1826 *Implemented MVP in the PR:* Run the node js process by default with "--expose-gc" and give the user the chance to force garbage collection in memory intensive actions. Document and/or blog about the use case. *Advanced Proposal 1* We could run the garbage collector anytime after the user code has been executed in our nodejs skeleton app. This would result in a constant 30ms overhead on top of the users action (see experiment in PR) *Advanced Proposal 2* Automatically detect memory intensive actions by gathering the memory consumption on the node process and force the GC if necessary *Advanced Proposal 3* Provide a flag in the create action API to define whether the GC should be enforced for the action. Feedback / comments welcome! kind regards, Jeremias Werner
